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Tropical Storm Marie Discussion Number 29
NWS National Hurricane Center Miami FL EP182020
1100 PM HST Mon Oct 05 2020
A 6/0630Z ASCAT-B scatterometer overpass indicated that Marie has
refused to weaken despite the deep convection being severely sheared
to the northeast of the low-level center. A solid area of 40-kt was
present northwest through northeast of the center, with a couple of
45-kt vectors present. However, the 45-kt vectors look like they
could have been rain enhanced, so the initial intensity remains at
40 kt for this advisory.
The initial motion estimate is 300/08 kt. There are no significant
changes to the previous forecast track or reasoning. Marie is
expected to move slowly west-northwestward along the southern
periphery of a deep-layer ridge for the next 24 hours or so, during
which time the cyclone will gradually spin down and become more
vertically shallow. Thereafter, and continuing until dissipation
occurs, a more westward motion is anticipated when the shallow
system will be steered by the low-level easterly tradewind flow. The
new NHC forecast track is similar to but a tad north of the
previous advisory track, and lies near the middle of the tightly
packed consensus aids.
Although Marie has managed to survive some horrendous southwesterly
vertical wind of at least 30 kt, the cyclone is not long for this
world due to the shear increasing further while the cyclone moves
over sub-25 deg C sea-surface temperatures for the next few days.
These very unfavorable environmental conditions should result in all
convection being stripped away by late Tuesday morning, causing
Marie to degenerate into a 35-kt post-tropical cyclone. Further
weakening is anticipated, with Marie becoming a remnant low by
Tuesday night and dissipating by late Friday or Saturday over the
far western portion of the eastern Pacific basin.
FORECAST POSITIONS AND MAX WINDS
INIT 06/0900Z 21.7N 134.3W 40 KT 45 MPH
12H 06/1800Z 22.2N 135.5W 35 KT 40 MPH...POST-TROPICAL
24H 07/0600Z 22.7N 136.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 07/1800Z 23.0N 137.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 08/0600Z 23.2N 138.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 08/1800Z 23.1N 139.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 09/0600Z 23.2N 140.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 10/0600Z...DISSIPATED
$$
Forecaster Stewart
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